Spray devices commonly referred to as spray balls are used to facilitate cleaning the interior surface of certain clean-in-place (CIP) equipment. Equipment that can be more quickly and cost effectively cleaned without disassembling the equipment is often referred to as clean-in-place equipment. Liquid cleaning compositions are typically run through clean-in-place equipment in order to provide cleaning. Exemplary facilities that utilize clean-in-place technology include dairy processing facilities, breweries, and chemical processing plants. Pipes and lines are often cleaned by running a cleaning composition therethrough. In order to reach the walls of vessels, spray balls are often used to project a liquid against the surface of the vessel. Exemplary types of vessels that are often cleaned with a spray device include tanks such as fermentation tanks, aging tanks, holding tanks, mixers, reactors, etc. Spray devices are often designed to distribute cleaning composition and rinse composition relatively uniformly to the upper surfaces of the vessel to be cleaned allowing the compositions to flow by gravity to the bottom where it is returned to the CIP unit or allowed to drain. The spray devices are often designed to provide complete coverage over all the interior surfaces of the vessel.
Two generally available types of spray devices for application of cleaning composition and rinse to the interior surfaces of a vessel include fixed (static) spray devices and rotating (dynamic) spray devices. Fixed spray devices are often used in sanitary applications because there are no moving parts to maintain or to break down and risk contamination. Fixed spray devices generally operate at low pressure (20-25 psig) on the principle of cascading water flow or sheeting over the interior surface of the vessel. Detergents can be provided to loosen the soil while the bulk solution flow flushes the soils away. Rotating spray devices generally operate at lower volumes and higher pressures (greater than 30 psig) but also rely on the cascading flow of the cleaning composition over the interior surface of the vessel for the removal of soil.
The use of a two-phase liquid/gas stream to clean pipelines is disclosed in European Patent Application 0 490 117 A1 to Kuebler that was published on Jun. 17, 1992. Kuebler describes cleaning pipelines using a two-phase liquid/gas stream and a reduction in throughput of the cleaning liquid by several orders of magnitude relative to conventional clean-in-place techniques.
Additional publications describing mixed phased flow include, for example, U.S. Pat. No. 6,326,340 to Labib et al.; U.S. Pat. No. 6,454,871 to Labib et al.; and U.S. Pat. No. 6,027,572 to Labib et al.